142 RURAL BIRD LIFE. 



Some persons have most erroneously, though probably 

 unintentionally, advanced theories endeavouring to show 

 MS what purpose these caudal movements serve. They 

 have told us that when the Wagtail jerks his tail it is for 

 the purpose of disturbing the insects around him, just as 

 the cows lash their tails to drive away the troublesome 

 flies ; with this difference, however, the Wagtail disturbs 

 them for the purpose of preying on them, and the kine 

 for the purpose of driving them away. Now let the 

 young naturalist observe the Wagtail, it matters not of 

 what species, and he will find that these tail-jerking 

 motions are present even if the bird is not in search of 

 food ; besides, a bird possessing such keen powers of vision 

 does not require to hunt with his tail for sustenance. Did 

 this little volume treat with the anatomy of birds, it 

 would be an easy task to show the cause of these tail- 

 jerking motions ; but it will suffice to say that these 

 motions, and the extraordinary length of tail found in 

 this family of birds, goes far to aid in preserving the equili- 

 brium of the bird. 



The Yellow Wagtail is an associate with the cattle. 

 We see them running round them, under their bellies, or 

 even within a few inches of their mouth, and yet the 

 cattle view them not as enemies, nor attempt to drive 

 them away, for it would seem they know full well what 

 service they derive from these little songsters. Insects 

 innumerable torment them, and the Yellow Wagtail is 

 busily employed ridding them of their pests. Now with 

 a short call note they launch into the air, to secure an 

 insect, and then with dainty motions run nimbly for- 

 ward to capture an unlucky beetle. They are not at 

 all shy, and, provided you advance with caution, you can 

 approach and view their actions when but a itw yards 

 away. When the ground is being ploughed in early 



